import { NextRequest, NextResponse } from 'next/server'
import { writeFile, readFile, mkdir } from 'fs/promises'
import { existsSync } from 'fs'
import path from 'path'

// Speicherort fuer Uploads
const UPLOADS_DIR = '/tmp/breakpilot-uploads'
const METADATA_FILE = path.join(UPLOADS_DIR, 'metadata.json')

interface UploadedFile {
  id: string
  sessionId: string
  name: string
  type: string
  size: number
  uploadedAt: string
  dataUrl: string // Base64 data URL
}

// Stelle sicher, dass das Upload-Verzeichnis existiert
async function ensureUploadsDir() {
  if (!existsSync(UPLOADS_DIR)) {
    await mkdir(UPLOADS_DIR, { recursive: true })
  }
}

// Lade Metadaten
async function loadMetadata(): Promise<UploadedFile[]> {
  try {
    await ensureUploadsDir()
    if (existsSync(METADATA_FILE)) {
      const data = await readFile(METADATA_FILE, 'utf-8')
      return JSON.parse(data)
    }
  } catch (error) {
    console.error('Error loading metadata:', error)
  }
  return []
}

// Speichere Metadaten
async function saveMetadata(uploads: UploadedFile[]) {
  await ensureUploadsDir()
  await writeFile(METADATA_FILE, JSON.stringify(uploads, null, 2))
}

// GET: Liste alle Uploads fuer eine Session
export async function GET(request: NextRequest) {
  const sessionId = request.nextUrl.searchParams.get('sessionId')

  const uploads = await loadMetadata()

  if (sessionId) {
    const filtered = uploads.filter(u => u.sessionId === sessionId)
    return NextResponse.json({ uploads: filtered })
  }

  // Alle Uploads (fuer Dashboard)
  return NextResponse.json({ uploads })
}

// POST: Neuen Upload hinzufuegen
export async function POST(request: NextRequest) {
  try {
    const body = await request.json()
    const { sessionId, name, type, size, dataUrl } = body

    if (!sessionId || !name || !dataUrl) {
      return NextResponse.json(
        { error: 'Missing required fields' },
        { status: 400 }
      )
    }

    const upload: UploadedFile = {
      id: `upload-${Date.now()}-${Math.random().toString(36).substr(2, 9)}`,
      sessionId,
      name,
      type: type || 'application/octet-stream',
      size: size || 0,
      uploadedAt: new Date().toISOString(),
      dataUrl
    }

    const uploads = await loadMetadata()
    uploads.push(upload)
    await saveMetadata(uploads)

    return NextResponse.json({ success: true, upload })
  } catch (error) {
    console.error('Upload error:', error)
    return NextResponse.json(
      { error: 'Upload failed' },
      { status: 500 }
    )
  }
}

// DELETE: Upload loeschen
export async function DELETE(request: NextRequest) {
  const id = request.nextUrl.searchParams.get('id')

  if (!id) {
    return NextResponse.json(
      { error: 'Missing upload id' },
      { status: 400 }
    )
  }

  const uploads = await loadMetadata()
  const filtered = uploads.filter(u => u.id !== id)
  await saveMetadata(filtered)

  return NextResponse.json({ success: true })
}